This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-359547, filed Dec. 17, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a camera distance measurement apparatus allowing to measure the distance of a wide extent in a photographic picture and, more in detail, a wide field distance measurement apparatus.
Recently, various AF (auto-focus) cameras have been developed for focusing on the point, by measuring the distances of a plurality of points in an area to be shot. These AFs are generally called xe2x80x9cmulti AFxe2x80x9d and more the number of points that can be measured increase, more important is the technology to decide the position whose distance is to be measured.
Concerning such multi AF technology, the Applicant has proposed a technology to measure the distance giving priority to an object having the breadth of man""s shoulders by Jpn. Pat. Appln. KOKAI Publication No. 7-19858.
However, though the technology described in the aforementioned Jpn. Pat. Appln. KOKAI Publication No. 7-19858 gives priority to an object having the breadth of man""s shoulders, it did not correspond to a technology expanding the area whose distance can be measured in the two-dimensional directions in the picture.
Therefore, an object of the present invention is to provide a distance measurement apparatus that can decide the distance measurement point effectively and rapidly, and focus exactly, even for an apparatus expanding the area whose distance can be measured in the two-dimensional directions in the picture.
In other words, a first object of the present invention it to provide
a distance measurement apparatus measuring the distances of a plurality of points in an area to be shot, comprising:
a flash circuit for projecting flashlight into the area to be shot;
an area sensor for receiving light of the flashlight reflected from an object, provided with a plurality of pixels arranged two-dimensionally;
an A/D converter for converting respective pixel output of the area sensor into digital value, and outputting digital picture data; and
a calculation control circuit for detecting a main object position in the area to be shot based on the digital picture data and, at the same time, setting the distance measurement point on the main object position, the calculation control circuit including:
an extraction section to extract a plurality of line data from the digital picture data;
a judgment section for judging a part where the signal level varies at a predetermined value or more between adjacent pixels, for each of line data extracted by the extraction section;
a detection section for detecting the main object position, by comparing the part judged by the judgment section, for the plurality of line data; and
a setting section for setting the distance measurement point at the main object position detected by the detection section (corresponding to claim 1).
A second object of the present invention is to provide a distance measurement apparatus measuring the distance of a plurality of points in an area to be shot, comprising:
light projection means for projecting into the area to be shot;
an area sensor provided with a plurality of pixels arranged two-dimensionally;
extraction means to extract output from a plurality of pixel rows arranged on a straight line of the area sensor when the light is projected;
detection means for judging the presence or absence of a particular pattern part for the output of respective pixel row extracted by the extraction means, and detecting the object image pattern by comparing respective particular pattern part; and
setting means for identifying the main object based on the image pattern detected by the detection means, and setting the distance measurement point at this position.
A third object of the present invention is to provide a distance measurement apparatus measuring the distance of a plurality of points in an area to be shot, comprising:
shooting means including an area sensor, for detecting images distributed in the area to be shot;
extraction means for extracting output from a plurality of pixel rows arranged in a straight line of the area sensor plane, and output from the other pixel rows parallel to the pixel rows;
judgment means for judging a part where the signal level varies at a predetermined value or more between adjacent pixels, for each of line data extracted by the extraction means; and
setting means for identifying the main object position based on the information concerning the part in respective pixel rows judged by the judgment means, and setting the distance measurement point at this position.
The fourth object of the present invention is to provide a distance measurement apparatus, comprising:
an area sensor having an area extended respectively in the horizontal direction and vertical direction in an area to be shot;
extraction means for extracting sensor data rows in the horizontal direction in a predetermined ordinate in the vertical direction of the area sensor;
selection means for judging an vertical direction ordinate where the sensor data row varies, and selecting a particular vertical ordinate in the area sensor; and
distance measurement means for executing the distance measurement operation, with output of sensor data rows in he horizontal direction in the vertical ordinate selected by the selection means.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.